(19)
(11) EP 1 901 334 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
27.08.2008 Bulletin 2008/35

(43) Date of publication A2:
19.03.2008 Bulletin 2008/12

(21) Application number: 07021611.4

(22) Date of filing: 12.09.2003
(51) International Patent Classification (IPC): 
H01J 61/54(2006.01)
 H01J 61/56(2006.01)
(84) Designated Contracting States:
BE DE

(30) Priority: 13.09.2002 JP 2002267973
13.09.2002 JP 2002267974
19.09.2002 JP 2002273700
19.09.2002 JP 2002273701

(62) Application number of the earlier application in accordance with Art. 76 EPC:
03255707.6 / 1398824

(71) Applicant: MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD.
Osaka 571-8501 (JP)

(72) Inventors:
  • Takeda, Kazuo
    Sakai-shi Osaka 593-8305 (JP)
  • Ota, Isao c/o Matsushita Electric Ind. Co., Limited
    Chuo-ku, Osaka, 540-6207 (JP)
  • Sakamoto, Kazushige
    Otsu-shi Shiga 520-0054 (JP)
  • Nishiura, Yoshiharu
    Otsu-shi 520-0865 (JP)

(74) Representative: Crawford, Andrew Birkby et al
A.A. Thornton & Co., 235 High Holborn
London WC1V 7LE
London WC1V 7LE (GB)

   


(54) Metal halide lamp having function for suppressing abnormal discharge


(57) A metal halide lamp (21) includes a ceramic arc tube (5) that is composed of a main body (5a) and two narrow tube parts (5b,5c) provided at respective ends of the main body; a pair of electrodes provided inside the main body; two feeders (4a,4b), each being connected at one end thereof to a different one of the electrodes inside the main body, and extending through a different one of the narrow tube parts, so as to be external to the arc tube at another end; a starting wire (7) that is connected to one of the feeders (4a), and that is in a vicinity of or contacts an outer surface of the arc tube; and a circuit breaking element (6) that is on a current path of the starting wire, and cuts off current to the starting wire within a predetermined time from an abnormal discharge commencing, the predermined time being 10 seconds.







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